1. Field of the Invention
The present invention relates to a bit patterned medium having a super-track, a method of tracking a track of the bit patterned medium, a head appropriate for the bit patterned medium, and an information recording/reproducing apparatus including the bit patterned medium and the head.
2. Description of the Related Art
Since society has been rapidly developing toward becoming an industrial and information society, the amount of information to be processed has sharply increased, and thus, there is a demand for information recording/reproducing apparatuses to have high densities.
In particular, hard disk drives (HDDs) have characteristics such as large storage capacity and fast access time. Accordingly, the HDDs have been highlighted as information recording devices for various digital devices, as well as computers. The HDDs use a magnetic recording method or an electric recording method, so as to record/reproduce information.
The magnetic recording method applies a magnetic field and magnetizes a magnetic layer of a recording medium, thereby recording the information and allowing the information to be reproduced by a magnetic signal of the magnetized magnetic layer. In the case of a longitudinal magnetic recording method, whereby the information is recorded based on the fact that a magnetization direction of the magnetic layer is parallel to a surface of the magnetic layer, a recording density of 100 Gb/in2 is realized. A perpendicular magnetic recording method, whereby the information is recorded based on the fact that the magnetization direction of the magnetic layer is perpendicular to the surface of the magnetic layer, is more advantageous than the longitudinal magnetic recording method in view of the recording density, and realizes a recording density of over 500 Gb/in2.
An electric field recording method records and reproduces information by using an electric field instead of the magnetic field, and in this regard, much research is being conducted. The electric field recording method polarizes a ferroelectric layer of a recording medium by using the electric field, thereby recording the information and reproducing the information by using an electric signal of the polarized ferroelectric layer. The electric field recording method can realize a high recording density of over 1 Tb/in2.
An increase in the recording density by using any one of the aforementioned recording methods causes a decrease in the size of a bit which is a minimum unit for recording information, and weakens a signal generated from the recording medium. In order to solve these problems, research is being conducted, wherein the research is about increasing the recording density by using a patterned medium so that a signal to noise ratio (SNR) can be maintained high by reducing noise in the recording medium.
In the patterned medium, a recording layer, in which information is recorded, is patterned by a bit cell that is a unit for recording the information. For example, in the case of a magnetic recording medium, a magnetic body forming the recording layer is patterned by a plurality of bit cells. In the case of an electric field recording medium, a ferroelectric material forming the recording layer is patterned by a plurality of bit cells.